Civil unrest flared and curfews were imposed in several major United States (US) cities on Saturday as demonstrators took to the streets to vent outrage at the death of a black man shown on video gasping for breath as a white Minneapolis policeman knelt on his neck.

From Los Angeles to Miami to Chicago, protests marked by chants of “I can’t breathe” – a rallying cry echoing the dying words of George Floyd – began peacefully before turning unruly as demonstrators blocked traffic, set fires and clashed with riot police, some firing tear gas and plastic bullets in an effort to restore order.

Violent protests are continuing to spread across the United States

The sight of protesters flooding streets fueled a sense of crisis in the United States after weeks of lockdowns due to the coronavirus pandemic, which has seen millions thrown out of work and has disproportionately affected minority communities.

In the nation’s capital, hundreds of demonstrators assembled near the Justice Department headquarters shouting, “black lives matter.” Many later moved to the White House, where they faced off with shield-carrying police, some mounted on horseback.

President Donald Trump said on Saturday that if protesters who gathered the night before in Lafayette Square, across from the White House, had breached the fence, “they would have been greeted with the most vicious dogs, and most ominous weapons, I have ever seen.”

The full Minnesota National Guard was activated for the first time since World War Two after four nights of arson, looting and vandalism in parts of Minneapolis, the state’s largest city, and its adjacent capital, St. Paul.

Minnesota Governor Tim Walz said the deployment was necessary because outside agitators were using protests over Floyd’s death to sow chaos.

“We are under assault,” Walz, a first-term governor elected from Minnesota’s Democratic-Farmer-Labor Party, told a briefing on Saturday. “Order needs to be restored.”

Civil unrest flared and curfews were imposed in several major United States (US) cities on Saturday as demonstrators took to the streets to vent outrage at the death of a black man shown on video gasping for breath as a white Minneapolis policeman knelt on his neck., US Attorney General William Barr also pointed the finger at extremist instigators, though he and Walz – neither offering evidence to support their assertions – suggested opposite ends of the political fringe were to blame.

Civil rights activists said video of Floyd’s arrest on Monday – captured by an onlooker’s cellphone as he repeatedly groaned, “please, I can’t breathe” before he died – triggered an outpouring of rage long simmering over persistent racial bias in the US criminal justice system.

But the rapidly spreading protests also coincided with a deep-seated national discontent over the social claustrophobia and economic carnage wrought by the coronavirus pandemic.